1. Field Of The Invention
This invention is generally directed to an enclosure for gases and in a particular embodiment to an enclosure for helium. It is also directed to gas recovery, storage and recycling systems and, in one aspect, to a system for recovering and recycling helium which provides relatively pure helium while maintaining a relatively constant back pressure.
2. Description Of Related Art
Helium is a natural, non-replenishable resource that is readily naturally available from only one location on Earth. Helium cannot be economically produced by either artificial decay or by extraction from the atmosphere. One known method for capturing and storing a gas involves capturing used helium in a large balloon. The balloon is confined in a storage building to isolate it from environmental effects, particularly wind. However, as the balloon expands with helium, back pressure from the balloon as it fills increases. Also, water vapor from the environment and oil from a compressor used to transfer the helium to a storage tank or to a supply system can contaminate the helium.
U.S. Pat. No. 3,653,220 to Foster describes a process for the recovery of helium from a natural gas flow. This process is used to produce helium from a raw material gas.
U.S. Pat. No. 3,815,327 to Viland shows a hydrocarbon recovery system which collects gaseous vapors, condenses the vapors by refrigeration and dehydrates the vapors. Recovered gasoline is returned to an underground tank and impurities are vented to the atmosphere.
U.S. Pat. No. 4,845,334 to Stocks et al., teaches the capture, purification, and reuse of inert gases. The gases mentioned include argon and helium which are used in process control in plasma furnaces. A plasma furnace is shown having a vented passage to an inlet port of a recycling system. The gas is first cooled and filtered to remove dust, water vapor, and oxygen from the gas. Then an oiled compressor liquefies the gas which is pumped through an oil removing filter to a storage facility for reuse.
U.S. Pat. No. 5,017,204 to Gottier et al., discloses a means of recovering helium from a natural gas feed which is able to produce a crude helium product having three percent helium. The process is not related to recycling of used helium.
U.S. Pat. No. 5,080,694 to Knoblauch et al., discloses the recovery of helium from a natural gas having initial low concentrations of helium. Repeated absorption processes are used to produce helium with a 99.9 percent purity for use in balloons and the like. The recovery system assumes high levels of contamination.
U.S. Pat. No. 5,090,637 to Haunschild teaches a lighter-than-air aircraft having a helium recycling system. The system makes use of a catalytic conversion process which removes oxygen and nitrogen gases from the helium volume to a purity of 98-99 percent. Lift is increased by improving the purity as well as heating the lift gas in the process.
There has long been a need for a gas recycling system which does not contaminate the gas and which provides the gas for re-use in a relatively pure form. There has long been a need for such a system which has a variable volume enclosure and can receive gas in at a low pressure while pumping it out at a relatively high pressure. There has long been a need for such a system that can handle either high or low flow rates. There has long been a need for such systems which do not have undesirably high back pressure levels.